Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755328Ab0GNCA6 (ORCPT ); Tue, 13 Jul 2010 22:00:58 -0400 Received: from sh.osrg.net ([192.16.179.4]:34860 "EHLO sh.osrg.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752853Ab0GNCA4 (ORCPT ); Tue, 13 Jul 2010 22:00:56 -0400 Date: Wed, 14 Jul 2010 10:59:38 +0900 To: zpfeffer@codeaurora.org Cc: fujita.tomonori@lab.ntt.co.jp, linux@arm.linux.org.uk, ebiederm@xmission.com, linux-arch@vger.kernel.org, dwalker@codeaurora.org, mel@csn.ul.ie, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, andi@firstfloor.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [RFC 1/3 v3] mm: iommu: An API to unify IOMMU, CPU and device memory management From: FUJITA Tomonori In-Reply-To: <20100713121420.GB4263@codeaurora.org> References: <4C3C0032.5020702@codeaurora.org> <20100713150311B.fujita.tomonori@lab.ntt.co.jp> <20100713121420.GB4263@codeaurora.org> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: <20100714104353B.fujita.tomonori@lab.ntt.co.jp> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-3.0 (sh.osrg.net [192.16.179.4]); Wed, 14 Jul 2010 10:59:43 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1300 Lines: 26 On Tue, 13 Jul 2010 05:14:21 -0700 Zach Pfeffer wrote: > > You mean that you want to specify this alignment attribute every time > > you create an IOMMU mapping? Then you can set segment_boundary_mask > > every time you create an IOMMU mapping. It's odd but it should work. > > Kinda. I want to forget about IOMMUs, devices and CPUs. I just want to > create a mapping that has the alignment I specify, regardless of the > mapper. The mapping is created on a VCM and the VCM is associated with > a mapper: a CPU, an IOMMU'd device or a direct mapped device. Sounds like you can do the above with the combination of the current APIs, create a virtual address and then an I/O address. The above can't be a reason to add a new infrastructure includes more than 3,000 lines. > > Another possible solution is extending struct dma_attrs. We could add > > the alignment attribute to it. > > That may be useful, but in the current DMA-API may be seen as > redundant info. If there is real requirement, we can extend the DMA-API. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/